1. Field of the Invention
The present invention relates to a slotted set screw structure. Particularly, the present invention relates to the slotted set screw structure formed with various slot types.
2. Description of the Related Art
U.S. Pat. No. 7,883,308, entitled “SLOTTED SET SCREW,” discloses a conventional slotted set screw, as shown in FIG. 1, including a slot provided on an upper end surface and a first cut metal waste storing recess formed at each of two end portions of the slot. The first cut metal waste storing recess has two vertically cutting side walls and a tapered cutting bottom surface to form an enlarged opening. Formed between each of the vertically cutting side walls and the tapered cutting bottom surface is an inclined bottom edge line, identified as “A”, extending from the slot to an outer thread portion.
With continued reference to FIG. 1, however, in a forming process of the enlarged opening of the slot on the outer thread portion, formations of the two vertically cutting side walls, the tapered cutting bottom surface and the two inclined bottom edge lines “A” of the first cut metal waste storing recesses with respect to the outer thread portion inevitably result in great complexity of the entire screw-manufacturing process.
In addition, the tapered cutting bottom surface extends downward from a bottom surface of the slot such that a lower section of the enlarged opening expands downward on the outer thread portion with respect to the outer thread portion. Disadvantageously, the lower section of the enlarged opening results in an increase of the lower-section cut metal waste unexpectedly moving along the tapered cutting bottom surface to enter the first cut metal waste storing recess and the slot.
Furthermore, U.S. Pat. No. 7,883,308 discloses another conventional slotted set screw, as shown in FIG. 2, including a slot provided on an upper end surface and a second straight-line cut metal waste storing recess formed at each of two end portions of the slot on an outer thread portion. Each second cut metal waste storing recess has an extra enlarged straight-line cutting portion in comparing with the first cut metal waste storing recess, as shown in FIG. 1.
Referring again to FIG. 2, each second cut metal waste storing recess is formed with a vertically straight-line cutting wall intersecting with the slot generally perpendicular to the diametric direction and extending from an upper end towards but spaced from a lower end to the outer thread portion at circumferentially spaced locations on a cylindrical outer surface. Each second cut metal waste storing recess is further formed with a flat cutting bottom wall extending from the vertically straight-line cutting wall to the outer thread portion and is spaced from the upper end and the lower end.
With continued reference to FIG. 2, two end edges of the vertically straight-line cutting wall of each second cut metal waste storing recess connect straight through between two cut ends of threads whose remained circumferences are exceedingly shortened for a thread-screwing operation. Disadvantageously, formation of the two vertically straight cutting walls on an upper end of the slotted set screw results in weakening the entire structural strength the upper end (i.e., head portion) and the threads thereof.
However, there is a need of providing a longer circumference of the threads to strengthen the upper end portion (i.e., head portion) of the slotted set screw and also providing enlarged dimensions of each cut metal waste storing recess. The above-mentioned patent is incorporated herein by reference for purposes including, but not limited to, indicating the background of the present invention and illustrating the situation of the art.
As is described in greater detail below, the present invention provides a slotted set screw structure. A cut metal waste storing recess is formed with two vertical walls (or inclined walls) and a horizontal bottom surface on an upper end portion or a lower end portion of the slotted set screw. A horizontal bottom edge is formed between each of the two vertical walls (or inclined walls) and the horizontal bottom surface to reduce an amount of cutting dimensions of the upper end portion or the lower end portion in such a way as to strengthen the entire structure of the upper end portion or the lower end portion of the slotted set screw and the threads thereof.